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2d82e622 AB |
1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* | |
3 | * Originally from efivars.c | |
4 | * | |
5 | * Copyright (C) 2001,2003,2004 Dell <[email protected]> | |
6 | * Copyright (C) 2004 Intel Corporation <[email protected]> | |
7 | */ | |
8 | ||
9 | #include <linux/capability.h> | |
10 | #include <linux/types.h> | |
11 | #include <linux/errno.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/mm.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/string.h> | |
16 | #include <linux/smp.h> | |
17 | #include <linux/efi.h> | |
18 | #include <linux/device.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/ctype.h> | |
21 | #include <linux/ucs2_string.h> | |
22 | ||
23 | #include "internal.h" | |
24 | ||
25 | MODULE_IMPORT_NS(EFIVAR); | |
26 | ||
27 | static bool | |
28 | validate_device_path(efi_char16_t *var_name, int match, u8 *buffer, | |
29 | unsigned long len) | |
30 | { | |
31 | struct efi_generic_dev_path *node; | |
32 | int offset = 0; | |
33 | ||
34 | node = (struct efi_generic_dev_path *)buffer; | |
35 | ||
36 | if (len < sizeof(*node)) | |
37 | return false; | |
38 | ||
39 | while (offset <= len - sizeof(*node) && | |
40 | node->length >= sizeof(*node) && | |
41 | node->length <= len - offset) { | |
42 | offset += node->length; | |
43 | ||
44 | if ((node->type == EFI_DEV_END_PATH || | |
45 | node->type == EFI_DEV_END_PATH2) && | |
46 | node->sub_type == EFI_DEV_END_ENTIRE) | |
47 | return true; | |
48 | ||
49 | node = (struct efi_generic_dev_path *)(buffer + offset); | |
50 | } | |
51 | ||
52 | /* | |
53 | * If we're here then either node->length pointed past the end | |
54 | * of the buffer or we reached the end of the buffer without | |
55 | * finding a device path end node. | |
56 | */ | |
57 | return false; | |
58 | } | |
59 | ||
60 | static bool | |
61 | validate_boot_order(efi_char16_t *var_name, int match, u8 *buffer, | |
62 | unsigned long len) | |
63 | { | |
64 | /* An array of 16-bit integers */ | |
65 | if ((len % 2) != 0) | |
66 | return false; | |
67 | ||
68 | return true; | |
69 | } | |
70 | ||
71 | static bool | |
72 | validate_load_option(efi_char16_t *var_name, int match, u8 *buffer, | |
73 | unsigned long len) | |
74 | { | |
75 | u16 filepathlength; | |
76 | int i, desclength = 0, namelen; | |
77 | ||
78 | namelen = ucs2_strnlen(var_name, EFI_VAR_NAME_LEN); | |
79 | ||
80 | /* Either "Boot" or "Driver" followed by four digits of hex */ | |
81 | for (i = match; i < match+4; i++) { | |
82 | if (var_name[i] > 127 || | |
83 | hex_to_bin(var_name[i] & 0xff) < 0) | |
84 | return true; | |
85 | } | |
86 | ||
87 | /* Reject it if there's 4 digits of hex and then further content */ | |
88 | if (namelen > match + 4) | |
89 | return false; | |
90 | ||
91 | /* A valid entry must be at least 8 bytes */ | |
92 | if (len < 8) | |
93 | return false; | |
94 | ||
95 | filepathlength = buffer[4] | buffer[5] << 8; | |
96 | ||
97 | /* | |
98 | * There's no stored length for the description, so it has to be | |
99 | * found by hand | |
100 | */ | |
101 | desclength = ucs2_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2; | |
102 | ||
103 | /* Each boot entry must have a descriptor */ | |
104 | if (!desclength) | |
105 | return false; | |
106 | ||
107 | /* | |
108 | * If the sum of the length of the description, the claimed filepath | |
109 | * length and the original header are greater than the length of the | |
110 | * variable, it's malformed | |
111 | */ | |
112 | if ((desclength + filepathlength + 6) > len) | |
113 | return false; | |
114 | ||
115 | /* | |
116 | * And, finally, check the filepath | |
117 | */ | |
118 | return validate_device_path(var_name, match, buffer + desclength + 6, | |
119 | filepathlength); | |
120 | } | |
121 | ||
122 | static bool | |
123 | validate_uint16(efi_char16_t *var_name, int match, u8 *buffer, | |
124 | unsigned long len) | |
125 | { | |
126 | /* A single 16-bit integer */ | |
127 | if (len != 2) | |
128 | return false; | |
129 | ||
130 | return true; | |
131 | } | |
132 | ||
133 | static bool | |
134 | validate_ascii_string(efi_char16_t *var_name, int match, u8 *buffer, | |
135 | unsigned long len) | |
136 | { | |
137 | int i; | |
138 | ||
139 | for (i = 0; i < len; i++) { | |
140 | if (buffer[i] > 127) | |
141 | return false; | |
142 | ||
143 | if (buffer[i] == 0) | |
144 | return true; | |
145 | } | |
146 | ||
147 | return false; | |
148 | } | |
149 | ||
150 | struct variable_validate { | |
151 | efi_guid_t vendor; | |
152 | char *name; | |
153 | bool (*validate)(efi_char16_t *var_name, int match, u8 *data, | |
154 | unsigned long len); | |
155 | }; | |
156 | ||
157 | /* | |
158 | * This is the list of variables we need to validate, as well as the | |
159 | * whitelist for what we think is safe not to default to immutable. | |
160 | * | |
161 | * If it has a validate() method that's not NULL, it'll go into the | |
162 | * validation routine. If not, it is assumed valid, but still used for | |
163 | * whitelisting. | |
164 | * | |
165 | * Note that it's sorted by {vendor,name}, but globbed names must come after | |
166 | * any other name with the same prefix. | |
167 | */ | |
168 | static const struct variable_validate variable_validate[] = { | |
169 | { EFI_GLOBAL_VARIABLE_GUID, "BootNext", validate_uint16 }, | |
170 | { EFI_GLOBAL_VARIABLE_GUID, "BootOrder", validate_boot_order }, | |
171 | { EFI_GLOBAL_VARIABLE_GUID, "Boot*", validate_load_option }, | |
172 | { EFI_GLOBAL_VARIABLE_GUID, "DriverOrder", validate_boot_order }, | |
173 | { EFI_GLOBAL_VARIABLE_GUID, "Driver*", validate_load_option }, | |
174 | { EFI_GLOBAL_VARIABLE_GUID, "ConIn", validate_device_path }, | |
175 | { EFI_GLOBAL_VARIABLE_GUID, "ConInDev", validate_device_path }, | |
176 | { EFI_GLOBAL_VARIABLE_GUID, "ConOut", validate_device_path }, | |
177 | { EFI_GLOBAL_VARIABLE_GUID, "ConOutDev", validate_device_path }, | |
178 | { EFI_GLOBAL_VARIABLE_GUID, "ErrOut", validate_device_path }, | |
179 | { EFI_GLOBAL_VARIABLE_GUID, "ErrOutDev", validate_device_path }, | |
180 | { EFI_GLOBAL_VARIABLE_GUID, "Lang", validate_ascii_string }, | |
181 | { EFI_GLOBAL_VARIABLE_GUID, "OsIndications", NULL }, | |
182 | { EFI_GLOBAL_VARIABLE_GUID, "PlatformLang", validate_ascii_string }, | |
183 | { EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 }, | |
184 | { LINUX_EFI_CRASH_GUID, "*", NULL }, | |
185 | { NULL_GUID, "", NULL }, | |
186 | }; | |
187 | ||
188 | /* | |
189 | * Check if @var_name matches the pattern given in @match_name. | |
190 | * | |
191 | * @var_name: an array of @len non-NUL characters. | |
192 | * @match_name: a NUL-terminated pattern string, optionally ending in "*". A | |
193 | * final "*" character matches any trailing characters @var_name, | |
194 | * including the case when there are none left in @var_name. | |
195 | * @match: on output, the number of non-wildcard characters in @match_name | |
196 | * that @var_name matches, regardless of the return value. | |
197 | * @return: whether @var_name fully matches @match_name. | |
198 | */ | |
199 | static bool | |
200 | variable_matches(const char *var_name, size_t len, const char *match_name, | |
201 | int *match) | |
202 | { | |
203 | for (*match = 0; ; (*match)++) { | |
204 | char c = match_name[*match]; | |
205 | ||
206 | switch (c) { | |
207 | case '*': | |
208 | /* Wildcard in @match_name means we've matched. */ | |
209 | return true; | |
210 | ||
211 | case '\0': | |
212 | /* @match_name has ended. Has @var_name too? */ | |
213 | return (*match == len); | |
214 | ||
215 | default: | |
216 | /* | |
217 | * We've reached a non-wildcard char in @match_name. | |
218 | * Continue only if there's an identical character in | |
219 | * @var_name. | |
220 | */ | |
221 | if (*match < len && c == var_name[*match]) | |
222 | continue; | |
223 | return false; | |
224 | } | |
225 | } | |
226 | } | |
227 | ||
228 | bool | |
229 | efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data, | |
230 | unsigned long data_size) | |
231 | { | |
232 | int i; | |
233 | unsigned long utf8_size; | |
234 | u8 *utf8_name; | |
235 | ||
236 | utf8_size = ucs2_utf8size(var_name); | |
237 | utf8_name = kmalloc(utf8_size + 1, GFP_KERNEL); | |
238 | if (!utf8_name) | |
239 | return false; | |
240 | ||
241 | ucs2_as_utf8(utf8_name, var_name, utf8_size); | |
242 | utf8_name[utf8_size] = '\0'; | |
243 | ||
244 | for (i = 0; variable_validate[i].name[0] != '\0'; i++) { | |
245 | const char *name = variable_validate[i].name; | |
246 | int match = 0; | |
247 | ||
248 | if (efi_guidcmp(vendor, variable_validate[i].vendor)) | |
249 | continue; | |
250 | ||
251 | if (variable_matches(utf8_name, utf8_size+1, name, &match)) { | |
252 | if (variable_validate[i].validate == NULL) | |
253 | break; | |
254 | kfree(utf8_name); | |
255 | return variable_validate[i].validate(var_name, match, | |
256 | data, data_size); | |
257 | } | |
258 | } | |
259 | kfree(utf8_name); | |
260 | return true; | |
261 | } | |
262 | ||
263 | bool | |
264 | efivar_variable_is_removable(efi_guid_t vendor, const char *var_name, | |
265 | size_t len) | |
266 | { | |
267 | int i; | |
268 | bool found = false; | |
269 | int match = 0; | |
270 | ||
271 | /* | |
272 | * Check if our variable is in the validated variables list | |
273 | */ | |
274 | for (i = 0; variable_validate[i].name[0] != '\0'; i++) { | |
275 | if (efi_guidcmp(variable_validate[i].vendor, vendor)) | |
276 | continue; | |
277 | ||
278 | if (variable_matches(var_name, len, | |
279 | variable_validate[i].name, &match)) { | |
280 | found = true; | |
281 | break; | |
282 | } | |
283 | } | |
284 | ||
285 | /* | |
286 | * If it's in our list, it is removable. | |
287 | */ | |
288 | return found; | |
289 | } | |
290 | ||
291 | static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor, | |
292 | struct list_head *head) | |
293 | { | |
294 | struct efivar_entry *entry, *n; | |
295 | unsigned long strsize1, strsize2; | |
296 | bool found = false; | |
297 | ||
298 | strsize1 = ucs2_strsize(variable_name, 1024); | |
299 | list_for_each_entry_safe(entry, n, head, list) { | |
300 | strsize2 = ucs2_strsize(entry->var.VariableName, 1024); | |
301 | if (strsize1 == strsize2 && | |
302 | !memcmp(variable_name, &(entry->var.VariableName), | |
303 | strsize2) && | |
304 | !efi_guidcmp(entry->var.VendorGuid, | |
305 | *vendor)) { | |
306 | found = true; | |
307 | break; | |
308 | } | |
309 | } | |
310 | return found; | |
311 | } | |
312 | ||
313 | /* | |
314 | * Returns the size of variable_name, in bytes, including the | |
315 | * terminating NULL character, or variable_name_size if no NULL | |
316 | * character is found among the first variable_name_size bytes. | |
317 | */ | |
318 | static unsigned long var_name_strnsize(efi_char16_t *variable_name, | |
319 | unsigned long variable_name_size) | |
320 | { | |
321 | unsigned long len; | |
322 | efi_char16_t c; | |
323 | ||
324 | /* | |
325 | * The variable name is, by definition, a NULL-terminated | |
326 | * string, so make absolutely sure that variable_name_size is | |
327 | * the value we expect it to be. If not, return the real size. | |
328 | */ | |
329 | for (len = 2; len <= variable_name_size; len += sizeof(c)) { | |
330 | c = variable_name[(len / sizeof(c)) - 1]; | |
331 | if (!c) | |
332 | break; | |
333 | } | |
334 | ||
335 | return min(len, variable_name_size); | |
336 | } | |
337 | ||
338 | /* | |
339 | * Print a warning when duplicate EFI variables are encountered and | |
340 | * disable the sysfs workqueue since the firmware is buggy. | |
341 | */ | |
342 | static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid, | |
343 | unsigned long len16) | |
344 | { | |
345 | size_t i, len8 = len16 / sizeof(efi_char16_t); | |
346 | char *str8; | |
347 | ||
348 | str8 = kzalloc(len8, GFP_KERNEL); | |
349 | if (!str8) | |
350 | return; | |
351 | ||
352 | for (i = 0; i < len8; i++) | |
353 | str8[i] = str16[i]; | |
354 | ||
355 | printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n", | |
356 | str8, vendor_guid); | |
357 | kfree(str8); | |
358 | } | |
359 | ||
360 | /** | |
361 | * efivar_init - build the initial list of EFI variables | |
362 | * @func: callback function to invoke for every variable | |
363 | * @data: function-specific data to pass to @func | |
2d82e622 AB |
364 | * @head: initialised head of variable list |
365 | * | |
366 | * Get every EFI variable from the firmware and invoke @func. @func | |
367 | * should call efivar_entry_add() to build the list of variables. | |
368 | * | |
369 | * Returns 0 on success, or a kernel error code on failure. | |
370 | */ | |
cdb46a8a AB |
371 | int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *, |
372 | struct list_head *), | |
2ce507f5 | 373 | void *data, struct list_head *head) |
2d82e622 | 374 | { |
f45812cc | 375 | unsigned long variable_name_size = 512; |
2d82e622 AB |
376 | efi_char16_t *variable_name; |
377 | efi_status_t status; | |
378 | efi_guid_t vendor_guid; | |
379 | int err = 0; | |
380 | ||
381 | variable_name = kzalloc(variable_name_size, GFP_KERNEL); | |
382 | if (!variable_name) { | |
383 | printk(KERN_ERR "efivars: Memory allocation failed.\n"); | |
384 | return -ENOMEM; | |
385 | } | |
386 | ||
387 | err = efivar_lock(); | |
388 | if (err) | |
389 | goto free; | |
390 | ||
391 | /* | |
f45812cc TS |
392 | * A small set of old UEFI implementations reject sizes |
393 | * above a certain threshold, the lowest seen in the wild | |
394 | * is 512. | |
2d82e622 AB |
395 | */ |
396 | ||
397 | do { | |
f45812cc | 398 | variable_name_size = 512; |
2d82e622 AB |
399 | |
400 | status = efivar_get_next_variable(&variable_name_size, | |
401 | variable_name, | |
402 | &vendor_guid); | |
403 | switch (status) { | |
404 | case EFI_SUCCESS: | |
405 | variable_name_size = var_name_strnsize(variable_name, | |
406 | variable_name_size); | |
407 | ||
408 | /* | |
409 | * Some firmware implementations return the | |
410 | * same variable name on multiple calls to | |
411 | * get_next_variable(). Terminate the loop | |
412 | * immediately as there is no guarantee that | |
413 | * we'll ever see a different variable name, | |
414 | * and may end up looping here forever. | |
415 | */ | |
2ce507f5 | 416 | if (variable_is_present(variable_name, &vendor_guid, |
2d82e622 AB |
417 | head)) { |
418 | dup_variable_bug(variable_name, &vendor_guid, | |
419 | variable_name_size); | |
420 | status = EFI_NOT_FOUND; | |
421 | } else { | |
422 | err = func(variable_name, vendor_guid, | |
cdb46a8a | 423 | variable_name_size, data, head); |
2d82e622 AB |
424 | if (err) |
425 | status = EFI_NOT_FOUND; | |
426 | } | |
427 | break; | |
428 | case EFI_UNSUPPORTED: | |
429 | err = -EOPNOTSUPP; | |
430 | status = EFI_NOT_FOUND; | |
431 | break; | |
432 | case EFI_NOT_FOUND: | |
433 | break; | |
f45812cc TS |
434 | case EFI_BUFFER_TOO_SMALL: |
435 | pr_warn("efivars: Variable name size exceeds maximum (%lu > 512)\n", | |
436 | variable_name_size); | |
437 | status = EFI_NOT_FOUND; | |
438 | break; | |
2d82e622 | 439 | default: |
f45812cc | 440 | pr_warn("efivars: get_next_variable: status=%lx\n", status); |
2d82e622 AB |
441 | status = EFI_NOT_FOUND; |
442 | break; | |
443 | } | |
444 | ||
445 | } while (status != EFI_NOT_FOUND); | |
446 | ||
447 | efivar_unlock(); | |
448 | free: | |
449 | kfree(variable_name); | |
450 | ||
451 | return err; | |
452 | } | |
453 | ||
454 | /** | |
455 | * efivar_entry_add - add entry to variable list | |
456 | * @entry: entry to add to list | |
457 | * @head: list head | |
458 | * | |
459 | * Returns 0 on success, or a kernel error code on failure. | |
460 | */ | |
461 | int efivar_entry_add(struct efivar_entry *entry, struct list_head *head) | |
462 | { | |
463 | int err; | |
464 | ||
465 | err = efivar_lock(); | |
466 | if (err) | |
467 | return err; | |
468 | list_add(&entry->list, head); | |
469 | efivar_unlock(); | |
470 | ||
471 | return 0; | |
472 | } | |
473 | ||
474 | /** | |
475 | * __efivar_entry_add - add entry to variable list | |
476 | * @entry: entry to add to list | |
477 | * @head: list head | |
478 | */ | |
479 | void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head) | |
480 | { | |
481 | list_add(&entry->list, head); | |
482 | } | |
483 | ||
484 | /** | |
485 | * efivar_entry_remove - remove entry from variable list | |
486 | * @entry: entry to remove from list | |
487 | * | |
488 | * Returns 0 on success, or a kernel error code on failure. | |
489 | */ | |
490 | void efivar_entry_remove(struct efivar_entry *entry) | |
491 | { | |
492 | list_del(&entry->list); | |
493 | } | |
494 | ||
495 | /* | |
496 | * efivar_entry_list_del_unlock - remove entry from variable list | |
497 | * @entry: entry to remove | |
498 | * | |
499 | * Remove @entry from the variable list and release the list lock. | |
500 | * | |
501 | * NOTE: slightly weird locking semantics here - we expect to be | |
502 | * called with the efivars lock already held, and we release it before | |
503 | * returning. This is because this function is usually called after | |
504 | * set_variable() while the lock is still held. | |
505 | */ | |
506 | static void efivar_entry_list_del_unlock(struct efivar_entry *entry) | |
507 | { | |
508 | list_del(&entry->list); | |
509 | efivar_unlock(); | |
510 | } | |
511 | ||
512 | /** | |
513 | * efivar_entry_delete - delete variable and remove entry from list | |
514 | * @entry: entry containing variable to delete | |
515 | * | |
516 | * Delete the variable from the firmware and remove @entry from the | |
517 | * variable list. It is the caller's responsibility to free @entry | |
518 | * once we return. | |
519 | * | |
520 | * Returns 0 on success, -EINTR if we can't grab the semaphore, | |
521 | * converted EFI status code if set_variable() fails. | |
522 | */ | |
523 | int efivar_entry_delete(struct efivar_entry *entry) | |
524 | { | |
525 | efi_status_t status; | |
526 | int err; | |
527 | ||
528 | err = efivar_lock(); | |
529 | if (err) | |
530 | return err; | |
531 | ||
532 | status = efivar_set_variable_locked(entry->var.VariableName, | |
533 | &entry->var.VendorGuid, | |
534 | 0, 0, NULL, false); | |
535 | if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) { | |
536 | efivar_unlock(); | |
537 | return efi_status_to_err(status); | |
538 | } | |
539 | ||
540 | efivar_entry_list_del_unlock(entry); | |
541 | return 0; | |
542 | } | |
543 | ||
544 | /** | |
545 | * efivar_entry_size - obtain the size of a variable | |
546 | * @entry: entry for this variable | |
547 | * @size: location to store the variable's size | |
548 | */ | |
549 | int efivar_entry_size(struct efivar_entry *entry, unsigned long *size) | |
550 | { | |
551 | efi_status_t status; | |
552 | int err; | |
553 | ||
554 | *size = 0; | |
555 | ||
556 | err = efivar_lock(); | |
557 | if (err) | |
558 | return err; | |
559 | ||
560 | status = efivar_get_variable(entry->var.VariableName, | |
561 | &entry->var.VendorGuid, NULL, size, NULL); | |
562 | efivar_unlock(); | |
563 | ||
564 | if (status != EFI_BUFFER_TOO_SMALL) | |
565 | return efi_status_to_err(status); | |
566 | ||
567 | return 0; | |
568 | } | |
569 | ||
570 | /** | |
571 | * __efivar_entry_get - call get_variable() | |
572 | * @entry: read data for this variable | |
573 | * @attributes: variable attributes | |
574 | * @size: size of @data buffer | |
575 | * @data: buffer to store variable data | |
576 | * | |
577 | * The caller MUST call efivar_entry_iter_begin() and | |
578 | * efivar_entry_iter_end() before and after the invocation of this | |
579 | * function, respectively. | |
580 | */ | |
581 | int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes, | |
582 | unsigned long *size, void *data) | |
583 | { | |
584 | efi_status_t status; | |
585 | ||
586 | status = efivar_get_variable(entry->var.VariableName, | |
587 | &entry->var.VendorGuid, | |
588 | attributes, size, data); | |
589 | ||
590 | return efi_status_to_err(status); | |
591 | } | |
592 | ||
593 | /** | |
594 | * efivar_entry_get - call get_variable() | |
595 | * @entry: read data for this variable | |
596 | * @attributes: variable attributes | |
597 | * @size: size of @data buffer | |
598 | * @data: buffer to store variable data | |
599 | */ | |
600 | int efivar_entry_get(struct efivar_entry *entry, u32 *attributes, | |
601 | unsigned long *size, void *data) | |
602 | { | |
603 | int err; | |
604 | ||
605 | err = efivar_lock(); | |
606 | if (err) | |
607 | return err; | |
608 | err = __efivar_entry_get(entry, attributes, size, data); | |
609 | efivar_unlock(); | |
610 | ||
611 | return 0; | |
612 | } | |
613 | ||
614 | /** | |
615 | * efivar_entry_set_get_size - call set_variable() and get new size (atomic) | |
616 | * @entry: entry containing variable to set and get | |
617 | * @attributes: attributes of variable to be written | |
618 | * @size: size of data buffer | |
619 | * @data: buffer containing data to write | |
620 | * @set: did the set_variable() call succeed? | |
621 | * | |
622 | * This is a pretty special (complex) function. See efivarfs_file_write(). | |
623 | * | |
624 | * Atomically call set_variable() for @entry and if the call is | |
625 | * successful, return the new size of the variable from get_variable() | |
626 | * in @size. The success of set_variable() is indicated by @set. | |
627 | * | |
628 | * Returns 0 on success, -EINVAL if the variable data is invalid, | |
629 | * -ENOSPC if the firmware does not have enough available space, or a | |
630 | * converted EFI status code if either of set_variable() or | |
631 | * get_variable() fail. | |
632 | * | |
633 | * If the EFI variable does not exist when calling set_variable() | |
634 | * (EFI_NOT_FOUND), @entry is removed from the variable list. | |
635 | */ | |
636 | int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes, | |
637 | unsigned long *size, void *data, bool *set) | |
638 | { | |
639 | efi_char16_t *name = entry->var.VariableName; | |
640 | efi_guid_t *vendor = &entry->var.VendorGuid; | |
641 | efi_status_t status; | |
642 | int err; | |
643 | ||
644 | *set = false; | |
645 | ||
646 | if (efivar_validate(*vendor, name, data, *size) == false) | |
647 | return -EINVAL; | |
648 | ||
649 | /* | |
650 | * The lock here protects the get_variable call, the conditional | |
651 | * set_variable call, and removal of the variable from the efivars | |
652 | * list (in the case of an authenticated delete). | |
653 | */ | |
654 | err = efivar_lock(); | |
655 | if (err) | |
656 | return err; | |
657 | ||
2d82e622 AB |
658 | status = efivar_set_variable_locked(name, vendor, attributes, *size, |
659 | data, false); | |
660 | if (status != EFI_SUCCESS) { | |
661 | err = efi_status_to_err(status); | |
662 | goto out; | |
663 | } | |
664 | ||
665 | *set = true; | |
666 | ||
667 | /* | |
668 | * Writing to the variable may have caused a change in size (which | |
669 | * could either be an append or an overwrite), or the variable to be | |
670 | * deleted. Perform a GetVariable() so we can tell what actually | |
671 | * happened. | |
672 | */ | |
673 | *size = 0; | |
674 | status = efivar_get_variable(entry->var.VariableName, | |
675 | &entry->var.VendorGuid, | |
676 | NULL, size, NULL); | |
677 | ||
678 | if (status == EFI_NOT_FOUND) | |
679 | efivar_entry_list_del_unlock(entry); | |
680 | else | |
681 | efivar_unlock(); | |
682 | ||
683 | if (status && status != EFI_BUFFER_TOO_SMALL) | |
684 | return efi_status_to_err(status); | |
685 | ||
686 | return 0; | |
687 | ||
688 | out: | |
689 | efivar_unlock(); | |
690 | return err; | |
691 | ||
692 | } | |
693 | ||
694 | /** | |
695 | * efivar_entry_iter - iterate over variable list | |
696 | * @func: callback function | |
697 | * @head: head of variable list | |
698 | * @data: function-specific data to pass to callback | |
699 | * | |
700 | * Iterate over the list of EFI variables and call @func with every | |
701 | * entry on the list. It is safe for @func to remove entries in the | |
702 | * list via efivar_entry_delete() while iterating. | |
703 | * | |
704 | * Some notes for the callback function: | |
705 | * - a non-zero return value indicates an error and terminates the loop | |
706 | * - @func is called from atomic context | |
707 | */ | |
708 | int efivar_entry_iter(int (*func)(struct efivar_entry *, void *), | |
709 | struct list_head *head, void *data) | |
710 | { | |
711 | struct efivar_entry *entry, *n; | |
712 | int err = 0; | |
713 | ||
714 | err = efivar_lock(); | |
715 | if (err) | |
716 | return err; | |
717 | ||
718 | list_for_each_entry_safe(entry, n, head, list) { | |
719 | err = func(entry, data); | |
720 | if (err) | |
721 | break; | |
722 | } | |
723 | efivar_unlock(); | |
724 | ||
725 | return err; | |
726 | } |